Two-constituent elastomer materials based on alkyl aziridine comprising a catalyst constituent that contains a boric acid complex

ABSTRACT

The invention relates to elastomer materials based on N-alkylaziridino compounds with a base component which contains the aziridino compounds and with a catalyst component which contains at least one acid-acting compound, both components being mixed before use, characterized in that, as acid-acting compound of the catalyst component, one or more boric acid complexes are used which can be obtained by reaction of boric acid and/or a boric acid derivative with at least one OH-functional compound, the OH functions being able to be present wholly or partly protected, and this reaction being carried out either as an upstream reaction between boric acid and/or a boric acid derivative and at least one such OH-functional compound or during or after the preparation of the catalyst component or by mixing the catalyst component with the base component which then contains at least one OH-functional compound. The elastomer materials are preferably used as dental impression materials, bite-registration materials and doubling materials.

This application is the national phase under 35 U.S.C. § 371 of PCTInternational Application No. PCT/EP00/08568 which has an Internationalfiling date of Sep. 1, 2000, which designated the United States ofAmerica.

The invention relates to improved elastomer materials based onN-alkylaziridino compounds.

In particular, the invention relates to elastomer materials which arecharacterized by an increased extensibility and are preferably used asdental impression materials, bite-registration materials and doublingmaterials.

The preparation of elastomer materials based on N-alkylaziridinopolyethers and their use in dental materials has been known for a longtime. Thus, for example, DE-C-1 745 810 describes the preparation ofshaped bodies based on aziridino polyethers.

In the documents DE-C-3 246 654, EP-A-0 421 371 and EP-A-0 110 429, theuse of aziridino polyethers in polyether impression materials isdescribed.

It is furthermore known that N-alkylaziridino compounds can cure whenexposed to the action of acid-acting compounds (H. Bestian, Methoden derOrganischen Chemie [Methods in Organic Chemistry] (Houben-Weyl), XII/1(1958)). The use of neutral sulphuric acid or sulphonic acid esters asstarter substances for the curing of N-alkylaziridino compounds isdescribed in DE-C-888 170.

The use of oxonium, ammonium and sulphonium salts as starter substancesis proposed in DE-C-914 325.

A summary of the starter substances used for the curing of aziridinocompounds is contained in O. C. DERMER, G. E. HAM, “Ethylenimine andother Aziridines” Academic Press (1969).

Accordingly, a large number of compound classes and compounds haveproved to be suitable polymerization initiators in principle. In thepractical curing of aziridino polyethers, however, it is very difficultto set the desired setting pattern with a sufficiently long processingtime and rapid final curing. This object can be achieved by the use ofspecial trisalkylsulphonium salts according to EP-A-0 279 238.

A disadvantage when using sulphonium salts as starter substances is thecompounds which form during curing, which have an unpleasant smell.

If strong acids are improperly used as starter substances, there can bean irritant effect on the skin, or corrosion phenomena can occur onmetals.

For use, the mechanical properties such as breaking strength andelongation at break of the cured dental materials are of greatimportance. These properties are in general at a low level when usingthe known starter substances.

The object of the invention is to provided curable preparationscontaining N-alkylaziridino compounds, during the use of which nounpleasantly smelling compounds form, the use of strong, corrosive acidsbeing avoided and the cured dental materials having improved mechanicalproperties.

This object is achieved by an improved elastomer material based onN-alkylaziridino compounds, with a base component which contains theaziridino compounds, and with a catalyst component which contains atleast one acid-acting compound, both components being mixed before use,characterized in that, as an acid-acting compound of the catalystcomponent, one or more boric acid complexes are used, which can beobtained by reaction of boric acid and/or a boric acid derivative withat least one OH-functional compound, the OH functions being able to bewholly or partly protected, and this reaction taking place either as anupstream reaction between boric acid and/or a boric acid derivative andat least one such OH-functional compound or during or after thepreparation of the catalyst component or by mixing the catalystcomponent with the base component which then contains one suchOH-functional compound.

The elastomer material preferably consists only of the base componentand the catalyst component.

The improved elastomer materials according to the invention are used forexample as dental impression materials, as bite-registration materialsand as doubling materials.

The cured materials surprisingly also display markedly improvedmechanical properties. Clearly, the mechanical properties, such asbreaking strength and elongation at break of the cured materials, can beinfluenced through the selection of starter substances.

The boric acid or the boric acid derivatives used as a constituent ofthe catalyst component are used in a proportion by mass of 0.1 to 100%of the catalyst compound.

Favourable results with regard to the improvement of the mechanicalproperties can be achieved if the ratio of the number of mols of boricacid to the number of aziridino equivalents in the cured materials is1:1 to 1:20, preferably 1:1.2 to 1:10 and particularly preferably 1:1.5to 1:6, the aziridino equivalent mass of the N-alkylaziridino compoundsused lying in the range from 500 to 25000 g/equivalent, preferably inthe range from 1000 to 8000 g/equivalent and particularly preferably inthe range from 2000 to 6000 g/equivalent.

It has long been known that polyol compounds such as sugar, sugaralcohols, sugar acids and uronic acids form ester-like complexes withboric acid. A summary of the analytically relevant results is containedin “Treatise on Analytical Chemistry”, Part II, Vol. 10, Wiley, NewYork.

This complex formation is associated with an increase in acidity andallows the easily-realized alkalimetric titration of boric acid.

Complex formation is however also used in chromatographic andconductimetric analysis processes and in processes for the industrialextraction of boric acid from aqueous mixtures containing same.

Well-examined complexing agents for boric acid with regard toalkalimetric titration are fructose, glycose, mannitol, sorbitol andglycerol; the ionisation constants and the stability constants of therespective complexes are given (W. A. Nasarenko et al., Zaw. Lab. 34(1968), 257).

Surprisingly it was found that boric acid complexes withOH-functionalized compounds are in a position to effect the curing ofN-alkylaziridino compounds at room temperature and at a useful speed,which is mostly not the case with Brönsted acids which possessapproximately the same pK_(s) value as these complexes.

The discovery that, by using selected polyol boric acid complexes, thelevel of the mechanical properties can be clearly improved was alsowholly surprising.

It was furthermore found that both during the formation of the complexesand during the curing of the N-Alkylaziridino polyethers, nounpleasantly smelling compounds form.

Furthermore, the irritant effect of the catalyst component on the skin,for example when not properly used, and also the corrosive effect onbase metals can be markedly reduced or avoided through the choice ofcomplexing agents.

The reaction products of boric acid with OH-containing compounds, called“polyol boric acid complexes” in simple terms, to be used in the courseof the invention are prepared by reaction of boric acid or boric acidderivatives with compounds which preferably contain at least two OHgroups, compounds with only one OH group also being able to be used inthe complexing.

According to the invention, OH-functional compounds are used whichcontain at least one and up to 10 OH groups of the general structuralformula

-   -   R1, R2 and R3 representing the same or different radicals which        are hydrogen, aliphatic, cycloaliphatic, aromatic or araliphatic        substituents with 1 to 30 C atoms in each of which one or more C        atoms can be replaced by    -   R1 and R2 being the same or different and aliphatic,        cycloaliphatic, aromatic or araliphatic bivalent radicals with 1        to 30 C atoms.

In the complexing agents with two OH groups used according to apreferred version of the invention, these can be present in 1,2position, in 1,3 position or in a different position if the conformationof these compounds allows the formation of relatively stable complexes.The 1,2 position and the 1,3 position are preferred.

When using alcohols with more than two OH groups, different positions ofthese OH groups are possible. The 1,2,3 position such as is present insome sugars is favourable.

Complexing agents which have at least one phenolic OH group are used toadvantage. In this case, compounds are particularly preferred which alsocarry at least one other phenolic OH group or an aliphatic OH group andoptionally further substituents at the aromatic core.

Another preferred group of the complexing agents additionally orexclusively contains carboxylic OH groups. Particularly preferred inthis case are compounds which carry an aliphatic OH group in alphaposition relative to the carboxyl group.

Typical representatives of the complexing agents for the use accordingto the invention are:

-   1. Glycerol and its ether or ester derivatives as well as    alkoxy-extended glycerols and polyglycerols, such as for example    diglycerol, tetraglycerol, glycerol propoxylate,-   2. Alkylene glycols such as ethylene glycol and propylene glycol and    polyalkylene glycols such as for example polyethylene glycol,    polypropylene glycol, polyethylene glycol monomethyl ether,-   3. Mono- and multi-1,2-diols with alkyl radicals or alkylene bridges    such as for example 1,2-hexanediol, 1,2-cyclohexanediol,    3-chloropropan-1,2-diol, 1,2-propanediol,    3-mercapto-1,2-propanediol, pinacol, 3-bromopropan-1,2-diol,    1,2-butanediol and 1,2,9,10-tetrahydrodecane,-   4. Mono- and multi-1,3-diols with alkyl radicals or alkylene bridges    such as 1,3-butanediol, 2-ethyl-1,3-hexanediol,    2-ethyl-2-butylpropan-1,3-diol, 1,3-butanediol, 1,3-cyclohexanediol,    1,3-hexanediol, 2,2-diethylpropan-1,3-diol, 2,4-pentanediol,    2-methyl-2-propyl-1,3-propanediol, 2,2-dimethylpropan-1,3-diol, as    well as diols such as 1,5-butanediol, 1,6-hexanediol,    cis-2-buten-1,4-diol, 2-butin-1,4-diol, and alpha,    omega-OH-functionalized polymers such as poly-THF,-   5. Polyalcohols such as glucose, fructose, lactose, arabinose,    ribose, xylose, mannose, galactose, sorbose, xylulose, ribulose,    mannitol, sorbitol, maltitol, lactitol, gluconitrilol,    pentaerythritol, threitol, erythritol, arabitol,-   6. Hydroxycarboxylic acids such as gluconic acid, 2-ketogluconic    acid, mannosaccharic acid, mucic acid, glucuronic acid, quinic acid,    tartaric acid, ascorbic acid, mandelic acid, 4-chloromandelic acid,    lactic acid, glycolic acid, benzilic acid, vinylglucolic acid,    citric acid, phenyllactic acid, tropic acid, atrolactic acid,    dihydroxyfumaric acid, glycolic acid, quinic acid, hydroxymalonic    acid, 2-hydroxysuccinic acid, tartronic acid, salicylic acid,-   7. Esters of hydroxycarboxylic acids such as gluconic acid ethyl    ester, tartaric acid diethyl ester, tartaric acid dimethyl ester,    tartaric acid dibutyl ester, glycolic acid ethyl ester, xylitol    dimethacrylate,-   8. Dicarboxylic acids such as malonic acid, oxalic acid, fumaric    acid, maleic acid, 2,3-dibromosuccinic acid, succinic acid, glutaric    acid,-   9. Phenolic compounds such as pyrocatechol,    4-tert.-butylpyrocatechol, 3,5-di-tert.-butylpyrocatechol,    pyrogallol, salicylic alcohol, 3-methoxypyrocatechol,    2,3-dihydroxynaphthalene, 5-bromosalicylic alcohol,    5-chlorosalicylic alcohol, 4-chlorosalicylic alcohol,    3-chlorosalicylic alcohol, 3,5-dichlorosalicylic alcohol.

The use of several such OH-functional compounds is possible and can beexpedient to establish special properties such as for example a desiredchronological curing pattern.

The molar ratio between boric acid and the OH-functional compounds canbe varied within a wide range from 1:0.1 to 1:10, the range from 1:1 to1:4 being preferred.

The optimum ratio for each case depends on the necessary concentrationin each case and the solubility of the complex, the equilibrium positionand the effect of an excess of complexing agent on the properties of thedental materials.

Instead of boric acid, boric acid derivatives such as for example boricanhydride, borates and boric acid C₁₋₁₈, preferably C₂₋₄ esters can bewholly or partly used.

Furthermore the use of the starters according to the invention for thecuring of the N-alkylaziridino compounds is also possible in combinationwith other known starter substances such as Brönsted acids or sulphoniumsalts, the described negative effects of the last-mentioned startersbeing reduced and their positive effects, such as for example goodadjustability of the curing pattern being used.

There are various variants for the realization of the use according tothe invention of the boric acid complexes as starter substances ofpolyether curing.

According to the first variant, the reaction is carried out before theformulation of the catalyst component, and the ester-like boric acidcomplex is used as a constituent of the catalyst component.

The preparation of the complex takes place in per se known manner, forexample with the addition of toluene as entrainer for the water producedby esterification.

According to a second variant, the complexing of the boric acid iseffected by mixing of boric acid or a boric acid derivative with theOH-functionalized compound(s) during the formulation of the catalystcomponent, the water produced by esterification either remaining in thecatalyst component or being wholly or partly removed by suitablemeasures such as for example a vacuum treatment of the catalystcomponent.

Normally the formulation of the catalyst component takes place attemperatures in the range from 20 to 50° C., the application of highertemperatures can be expedient in accelerating the complexing or inestablishing the desired water content.

When using the first and second variants, the base component canoptionally also contain a neutral or basic-acting boric acid derivativesuch as for example alkali salts of boric acid or trialkyl esters ofboric acid.

According to a third variant, the complex starting the curing is formedonly after the mixing of the catalyst component with the base component,the catalyst component preferably containing the boric acid or a boricacid derivative and the base component the complexing agent.

According to a particular version of the third variant, the boric acidis present in the catalyst in a complexed or esterified form; aftermixing with the base component, a recomplexing takes place.

According to a further version of the third variant, the complexing ofthe boric acid is effected by one or more compounds in which the OHgroups of these compounds are derivatized. Upon mixing of the twocomponents, the reactive boric acid complexes are formed.

A derivatization of the OH groups can be achieved for example byesterification, etherification or silylation, silylation beingpreferred.

The silylated complexing agents can be used both in the base componentand in the catalyst component.

The listed variants and their versions can also be used in combinationwith each other. Such combinations can prove to be favourable inincreasing the storage stability of the catalyst and base components.

To achieve specific mechanical properties or to achieve a desiredsetting pattern, it can be expedient to use combinations of boric acidcomplexes with varying structure and composition.

Usually, the catalyst components contain according to the preferredfirst and second variant:

-   (A) 0.1 to 100 wt.-% of at least one boric acid complex, optionally    in an excess of complexing agent,-   (B) 0 to 95 wt.-% of at least one inert diluent,-   (C) 0 to 80 wt.-% of modifiers, including fillers, dyes, pigments,    thixotropic agents, flow-improvers, polymeric thickeners,    surfactants, stabilizers, polymerization-retarding compounds,    odorous substances and flavourings,    the wt-% data being related in each case to the overall mass of the    catalyst component;    and the base components:-   (D) 5 to 100 wt.-% of a mixture of N-alkylaziridino compounds with    aziridino equivalent masses of 500 to 25000 g/equivalent, preferably    in the range from 1000 to 8000 g/equivalent and particularly    preferably in the range from 2000 to 6000 g/equivalent,-   (E) 0 to 95 wt.-% of at least one inert diluent,-   (F) 0 to 80 wt.-% of modifiers, including fillers, dyes, pigments,    thixotropic agents, flow-improvers, polymeric thickeners,    surfactants, stabilizers, polymerization-retarding compounds,    odorous substances and flavourings,    the wt-% data being related in each case to the overall mass of the    base component;    and the components being stored separately and being mixed together    for processing in a catalyst component to base component ratio of    5:1 to 1:20, preferably 1:1 to 1:10.

There can be used, as inert diluents according to constituents (B) and(E), polyether polyols, such as for example polypropylene glycols ormixed polyetherols with tetrahydrofuran and/or ethylene oxide and/orpropylene oxide units, polyester polyols, such as for examplepolycaprolactone diols and polycaprolactone triols, polycarbonate diols,aliphatic esters, oils, fats, waxes, aliphatic hydrocarbons, araliphatichydrocarbons and also mono- or multifunctional esters of multivalentacids such as for example phthalic acid, adipinic acid or citric acid oresters or amides of alkylsulphonic acids and arylsulphonic acids.

Constituent (B) or (E) is used in quantities of 0 to 95 wt.-%,preferably 10 to 90 wt.-% and particularly preferably 40 to 85 wt.-%,relative to the overall weight of the catalyst component or the basecomponent.

As compounds according to the constituents (B) or (E), organic compoundscan be used which hydrophobize the total mixture and belong tocompletely different compound classes.

Good results are achieved with hydrocarbons with 6 to 30 C atoms whichare dissolved in the base component or can be incorporated in stablefine-particle form. The hydrocarbons can be aliphatic and/or aromaticand also olefinic and be present in branched and/or linear form.

Typical examples are polypropylene oils or polyisobutylene oils.Aromatic hydrocarbons such as for example polyphenylene compounds,dibenzyltoluene and dibenzylphenylmethane are used to advantage.

Waxy compounds with ester structures can also be used. Typicalrepresentatives of this compound class are the ester waxes such as aremarketed for example by Hoechst under the name Hoechst-Wachs E; F; X 22.

Modifiers can be added to the catalyst component and also to the basecomponent in a broad concentration range according to constituents (C)or (F). Constituents (C) or (F) are used in quantities of 0 to 80 wt.-%,preferably 0 to 50 wt.-% and particularly preferably in each case 15 to40 wt.-%, relative to the overall weight of the catalyst component orbase component.

These modifiers are mostly fine-particle fillers such as alumosilicates,silicic acids, quartz powder, wollastonite, mica powder and diatomaceousearth as well as dyes and pigments, the addition of which makes possiblea better assessment of the mixed product and reduces the danger ofconfusion, thixotropic agents such as finely-dispersed silicic acids andother additives influencing the flow behaviour, such as polymericthickeners, furthermore surfactants for establishing the flow-onbehaviour and also odorous substances and flavourings.

As constituent (D) of the base component, mixtures of N-alkylaziridinocompounds are used, the aziridino equivalent masses being able to bevaried from 500 to 25000 g/equivalent and the number of N-alkylaziridinogroups being able to be varied between 1 and 4 per molecule.

Preferably mixtures of N-alkylaziridino polyethers are used whichconsist of at least up to 60% of polyether compounds which carry atleast two aziridino groups. According to another preferred version ofthe invention, mixtures of N-alkylaziridino polyethers are used whichconsist of at least up to 5% of polyether compounds which contain atleast 3 aziridino groups.

Polyether basic bodies that can be used are those with tetrahydrofuranand/or ethylene oxide and/or propylene oxide units.

Preferably, the mixture of the N-alkylaziridino polyethers consists ofmixed-polyether derivatives of ethylene oxide and tetrahydrofuran,incorporated in a molar ratio of 1:2 to 1:5, preferably 1:3 to 1:4.

Constituent (D) is used in concentrations of 5 to 100 wt.-%, preferably20 to 70 wt.-% and particularly preferably 30 to 60 wt.-%, relative tothe overall weight of the base component.

To establish the desired setting pattern, the preparations according tothe invention according to constituent (C) or (F) can contain at leastone curing-retarding compound. In principle, amine or alkalinesubstances retard the curing of the N-alkylaziridino compounds and canbe used for this purpose.

Thus DE-A1-197 534 61, to the full contents of which reference is madehere, describes the use of 0.0005 to 50 wt.-% of soluble and/orfine-particle alkaline-earth and/or alkali metal compounds.

Thus for example solutions of lithium compounds, such as lithiumhydroxide or lithium carbonate, can be added to the catalyst componentand/or the base component. The use of lithium carboxylates is alsopossible.

The two-component preparations according to the invention based onN-alkylaziridino compounds can be used, depending on the composition ofthe catalyst component and the base component, for the gluing ofsubstrates, for sealing, coating and casting.

However, the preparations according to the invention are preferably usedfor the modelling of objects, models with accurate details beingobtained with the preparations according to the invention due to theirexcellent flow-on behaviour.

The preparations according to the invention are used to particularadvantage in dental modelling and in dental doubling.

In dental modelling, the good flow-on behaviour on the moist tooth andthe moist gum as well as the insensitivity of the precision of themodelling vis-à-vis saliva and blood proves to be of great advantage.

In dental doubling, the good flow-on behaviour on hydrophilic plastersurfaces and the good wettability of the obtained doublings with plasterpulp or admixed investment compound formulations is advantageous.

The dosing of the two components can be carded out by sight, for examplevia the so-called strand-length comparison, by weight, via pre-dosedpack units and subsequent manual admixing, from double-chamberedcartridges with static mixing tube or by means of volume dosing systemswith downstream static or dynamic mixers.

A high mixing quality is required to achieve optimum results. On theother hand, the tolerance of the mixing ratio is in general relativelyhigh and can for example cover the range from 0.75 to 1.25:5, with apreset catalyst component to base component ratio of 1:5, withoutuse-restricting property changes being ascertained.

The invention is described in more detail by the following exampleswithout being limited thereby.

EXAMPLES

1. Preparation and Testing of Impression Materials

With the help of laboratory kneaders, the catalyst components describedin Table 1 were prepared on 100-g scale. The preparation of the basecomponents which are described in Table 2 was carried out on 500-gscale.

Table 3 lists the mixtures which were examined using the catalystcomponents described in Table 1 and the base components described inTable 2, in the weight ratio indicated in each case. The mixtures wereprepared by smoothing onto the mixing block within 30 seconds and usedto determine the properties also listed in Table 3.

The mouth-removal time was able to be determined as the average value ofeach of 3 impressions from 3 different subjects in the form of acomplete upper-jaw impression.

All mixtures of examples 1 to 10 according to the invention (Table 3)yielded impressions which were not sticky after removal from the mouthand were characterized by a very good design sharpness.

The individual components and also the mixtures did not display anyunpleasant or noticeable odour.

2. Preparation and Testing of Doubling Materials

The catalyst components described in Table 4 were prepared on 100-gscale by mixing the organic components and incorporating the fillerswith the help of a dissolver and homogenizing in a laboratory kneader.

The preparation of the base components described in Table 5 took placeanalogously on 100 g scale, the organic thixotropic additive used(Thixatrol ST) being dissolved at 55°-60° before the incorporation ofthe fillers.

The properties, obtained upon mixing of the components in the weightratio 1:1, of the doubling materials are listed in Table 6.

The doubling materials according to invention examples 11 to 16 werecharacterized by an excellent design sharpness, a very good flow-onbehaviour on hydrophilic plaster surfaces and an excellent wetting ofthe obtained doublings with plaster pulp or the admixed investmentcompound.

3. Preparation and Testing of Bite-Registration Materials

The catalyst components described in Table 7 and the base componentsdescribed in Table 8 were prepared on 100-g or 500-g scale in laboratorykneaders.

Table 9 contains the characterization of the mixtures which wereprepared by smoothing onto the mixing block within 25 seconds.

Furthermore, Table 9 contains the processing time of the mixturesobtained at 23° C., the mouth-removal time, each measured from the startof mixing and the shore A hardness after 24 hours.

The bite-registration materials according to invention examples 17 to 20were characterized by a very high precision and were easy to cut andmill.

TABLE 1 Composition of the catalyst components for dental impressionmaterials Name of the catalyst components wt.-% AM- AM- AM- AM- AM- AM-Constituent K1 K2 K3 K4 K5 K6 Boric acid  3.72  3.57  3.81 —  1.10  3.70Salicylic alcohol 16.00 15.70 21.00 —  5.90 — Mandelic acid — — — — —19.60 Reaction product of boric — — — 15.30 12.70 — acid with salicylicalcohol in the molar ratio 1:2 Precipitation silicic acid 20.30 21.5020.00 21.00 23.70 20.20 (Sipernat D17) Statistical mixed — 58.53 — —25.30 — polyetherdiol, prepared from ethylene oxide and propylene oxidewith a molar mass of 3200 g/mol Polypropylene oxide diol — — 54.41 63.0030.60 55.80 with a molar mass of 2000 g/mol Polypropylene oxide diol59.28 — — — — — with a molar mass of 4000 g/mol Lithium hydroxide  0.08— Coloring paste, red  0.70  0.70  0.70  0.70  0.70  0.70

TABLE 2 Composition of the base components for dental impressionmaterials wt.-% Constituent AM-B1 AM-B2 AM-B3 Mixture of bisaziridinopolyethers with an 55.70 58.11 54.97 average imino equivalent mass of3100, prepared from a polyetherdiol which is composed of ethylene oxideand tetrahydrofuran units in the molar ratio 1:3.5 with a cyclicpolyether content of 0.27% Diatomaceous earth 10.69 11.50 14.00 (CelatomMW 25) Hydrogenated vegetable oil 13.91 12.51 14.72 Dibenzyl toluene17.80  9.08  9.41 Statistical mixed polyetherdiol, prepared —  6.90 —from ethylene oxide and propylene oxide with a molar mass of 3200 g/molPolypropylene oxide diol — —  5.00 with a molar mass of 2000 g/molColoring paste, grey  1.90  1.90  1.90

TABLE 3 Elastomer materials according to the invention using thecatalyst components according to Table 1 and base components accordingto Table 2 and determined properties Invention examples-No. 1 2 3 4 5 67 8 9 10 Catalyst component AM-K1 AM-K1 AM-K2 AM-K2 AM-K2 AM-K3 AM-K4AM-K5 AM-K5 AM-K6 Base component AM-B1 AM-B2 AM-B1 AM-B2 AM-B3 AM-B1AM-B3 AM-B1 AM-82 AM-B1 Mixing ratio 1:4.7 1:5.4 1:4.9 1:5.1 1:4.6 1:5.01:5.1 1:5.2 1:4.8 1:5.0 (by weight) C:B Start of curing at 23° C. 120120 130 125 135 150 125 145 140 40 (seconds) Mouth-removal time(seconds) 260 245 280 270 290 275 280 250 240 120 Elongation at break/%235 255 246 257 242 285 320 380 360 140 Tensile strength/MPa 1.65 1.751.89 1.85 1.95 1.84 1.90 2.01 2.10 1.35 Shore A hardness after 24 h 4852 49 51 53 49 50 48 51 50

TABLE 4 Composition and viscosity of the catalyst components fordoubling materials wt.-% DM- DM- DM- DM- DM- DM- Constituent K1 K2 K3 K4K5 K6 Boric acid  0.65  0.63  0.66 —  0.65  0.724-tert.-butylpyrocatechol  3.49  3.42  3.55 — — — Pyrocatechol,silanized — — — —  7.00 — with dichlorodimethylsilane Reaction productof boric — — —  2.40 — — acid with pyrocatechol in the molar ratio1:1.95 1,6-hexanediol  4.00  4.50 — —  4.50 — L-(+)-tartaric acid — 6.00 — — — — diethylester cis-1,4-butenediol — —  5.86 — — — Glycolicacid — — — — — 0.8 Glycerol — — — — —  1.65 Alkyl sulphonic acid ester11.86  5.45 29.22 13.60  9.85 18.83 of phenol (Mesamoll) Phthalic acidpolyester 66.00 66.00 47.00 70.00 66.00 66.00 (Ultramoll PP)Precipitation silicic acid — —  4.90 — — — (Sipernat D10) Precipitationsilicic acid 10.00 10.00  8.80 — —  6.00 (Sipernat 22S) Pyrogenicsilicic acid  4.00  4.00 — 14.00 12.00  6.00 (HDK H 2000) Coloringpigment, yellow — —  0.01 — — — (Thermoplastgelb 084F) Viscosity of thecatalyst 3020 2480 1980 2250 2530 2620 component/mPa.s

TABLE 5 Composition and viscosities of the base components for doublingmaterials wt.-% Constituent DM-B1 DM-B2 DM-B3 Mixture of bisaziridinopolyethers with an 40.00 39.70 45.00 average imino equivalent mass of3120, prepared from a polyetherdiol which is composed of ethylene oxideand tetrahydrofuran units in the molar ratio 1:3.4 Diatomaceous earth16.00 15.30 10.00 (Celatom MW 25) Dioctyl adipate 38.24 42.4998 40.50(Plastomoll DOA) Block mixed polyether 5.00 — 2.50 (Synperonic PE/L 121)Modified castor oil derivative 0.75 1.00 — (Thixatrol ST) Modifiedlayered silicate — — 2.00 (Bentone SD-3) Coloring paste, white — 1.50 —(Lithopone) Dye, purple 0.01 — — (Makrolex Violett B) Dye, blue — 0.0002— (Thermoplast Blau 684) Viscosity of the base component/mPa.s 3460 30203950

TABLE 6 Tested mixtures and determined properties for doubling materialsInvention examples-No. 11 12 13 14 15 16 Catalyst DM-K1 DM-K2 DM-K4DM-K3 DM-K5 DM-K6 component (cf. Table 4) Base DM-B1 DM-B1 DM-B1 DM-B2DM-B1 DM-B3 component (cf. Table 5) Mixing ratio 1:1 1:1 1:1 1:1 1:1 1:1by weight Start of 195 675 135 315 240 215 curing/seconds End of 5201800 420 855 780 760 curing/seconds Shore A 23 19 18 22 16 25 hardnessafter 24 hours Tensile 13.5 15.4 9.5 16.7 10 14.1 strength/N Elongation131 192 127 201 160 170 at break/%

TABLE 7 Composition of the catalyst components for bite-registrationmaterials Name of the catalyst components Constituent BM-K1 BM-K2 BM-K3Reaction product of boric acid and — 10.40 12.15 salicylic alcohol inthe molar ratio 1:2.1 Reaction product of boric acid and 5- 19.80  4.70 2.75 bromosalicylic alcohol in the molar ratio 1:1.95 Salicylic alcohol— —  3.85 Polypropylene oxide diol with a molar 53.75 57.85 55.80 massof 2100 g/mol Precipitation silicic acid 25.70 26.30 24.70 (Sipemat D17)Coloring paste white  0.75  0.75  0.75

TABLE 8 Composition of the base components for bite-registrationmaterials Name of the base component wt.-% Constituent BM-B1 BM-B2Mixture of bisaziridino polyethers with an 58.10 25.00 average iminoequivalent mass of 3100, prepared from a polyetherdiol which is composedof ethylene oxide units and tetrahydrofuran units in the molar ratio1:3.6 and has a cyclic ether content of 0.31 Mixture of bisaziridinopolyethers with an — 29.75 average imino equivalent mass of 1600,prepared from a polyetherdiol which is composed of ethylene oxide unitsand tetrahydrofuran units in the molar ratio 1:3.4 and has a cyclicether content of 0.38 Diatomaceous earth 34.00 39.27 (Celatom MW 25)Hydrogenated vegetable oil  5.00  4.20 Dibenzyl toluene  2.90  1.68

TABLE 9 Bite-registration materials according to the invention using thecatalyst components according to Table 7 and the base componentsaccording to Table 8 and determined properties Invention examples-No. 1718 19 20 Catalyst component BM-K1 BM-K2 BM-K2 BM-K3 (cf. Table 7) Basecomponent BM-B1 BM-B1 BM-B2 BM-B2 (cf. Table 8) Mixing ratio (by weight)C:B 1:5.0 1:5.3 1:4.8 1:5.0 Processing time/seconds  50  45  70  80Mouth-removal time/seconds 140 120 160 150 Shore A hardness (after 24 h) 71  73  81  83

1. Elastomer material based on N-alkylaziridino compounds with a basecomponent which contains an aziridino compound and with a catalystcomponent which contains at least one acid-acting compound, bothcomponents being mixed before use, wherein, as the acid-acting compoundof the catalyst component, one or more boric acid complexes are usedwhich can be obtained by reaction of boric acid and/or a boric acidderivative with at least one OH-functional compound, the OH functionsbeing able to be present wholly or partly protected, and this reactionbeing carried out either as an upstream reaction between boric acidand/or a boric acid derivative and at least one such OH-functionalcompound or during or after the preparation of the catalyst component orby mixing the catalyst component with the base component which thencontains at least one such OH-functional compound and the at least oneOH-functional compound containing at least one and up to 10 OH groupswherein the OH-functional compound is selected from the group consistingof i) compounds which contain at least one 1,2-dihydroxy and/or at least1,3-dihydroxy group; ii) compounds which have at least one phenolic OHgroup; and iii) α-hydroxy-carboxylic acids, wherein the OH-functionalcompound containing at least one and up to 10 OH groups has the generalstructural formula

wherein R1, R2 and R3 represent the same or different radicals selectedfrom the group consisting of hydrogen, aliphatic, cycloaliphatic,aromatic and araliphatic substituents with 1 to 30 C atoms in each, ofwhich one or more C atoms can be replaced by

R1′ and R2′ being the same or different wherein R1′ and R2′ arealiphatic, cycloaliphatic, aromatic or araliphatic bivalent radicalswith 1 to 30 C atoms.
 2. Elastomer material according to claim 1,wherein the curing of the aziridino compounds takes place through boricacid complexes which correspond to the following general structuralformula,

in which the substituents R4 can be different or the same or bridgedwith each other and R4 can mean: hydrogen, an aliphatic, cycloaliphatic,aromatic or araliphatic radical with 1 to 30 C atoms and one or more Catoms can be replaced by

in which R5 is hydrogen or C1 to C12 alkyl and R4 and also R5 can carryone or more halogens, —CN, —OH, —SH, —COOH, —COO(C₁₋₁₈ alkyl), —NO₂,SO₃H, alkylthio-, keto- and also aldehyde groups as substituents. 3.Elastomer material according to one of claims 1 to 2, wherein thecatalyst component contains 0.1 to 100 wt.-% of boric acid complexeswith OH-functional compounds optionally in an excess of theseOH-functional compounds.
 4. Elastomer material according to claim 1,wherein the ratio of number of mols of boron in the catalyst componentto the number of aziridino equivalents in the mixed preparation is 1:1to 1:20.
 5. Elastomer material according to claim 1, wherein the boricacid complexes are prepared by reaction of boric acid or boric acidderivatives with compounds which contain at least two OH groups or inthat the boric acid complexes are prepared by reaction of boric acidesters with compounds which contain at least two OH groups.
 6. Elastomermaterial according to claim 1, wherein the reaction of the boric acid orthe boric acid derivative with the OH-functional compounds is carriedout before the formulation of the catalyst component and the ester-likeboric acid complex is used as a constituent of the catalyst component,or in that the reaction of the boric acid or the boric acid derivativewith the OH-functional compounds takes place during the formulation ofthe catalyst component, or in that the reaction of the boric acid or theboric acid derivative with the OH-functional compounds takes placeduring and after the mixing of the catalyst component with the basecomponent.
 7. Elastomer material according to claim 1, wherein theformation of the curing-triggering boric acid complex takes place duringand/or after the mixing of the catalyst component with the basecomponent from a boric acid derivative of the catalyst component and atleast one OH-functional compound with at least 2 OH groups of the basecomponent.
 8. Elastomer material according to claim 1, wherein theformation of the curing-triggering boric acid complex takes place duringand/or after the mixing of the catalyst component with the basecomponent at least partly from a boric acid derivative, preferably aboric acid ester, of the catalyst component and at least oneOH-functional compound of the base component.
 9. Elastomer materialaccording to claim 1, wherein a molar ratio between boric acid and theOH-functional compounds is from 1:0.1 to 1:10.
 10. Elastomer materialaccording to claim 1, wherein, as complexing agent for the boric acid,OH-functional organic compounds are used which contain at least one1,2-dihydroxy and/or at least one 1,3-dihydroxy group.
 11. Elastomermaterial according to claim 1, wherein OH-functional complexing agentsare used which have at least one phenolic OH group.
 12. Elastomermaterial according to claim 11, wherein, as complexing agent,pyrocatechol or 2,3-dihydroxynaphthalene is used, the phenyl radical(s)optionally being able to contain further substituents such as alkyl,halide, alkyl ester, alkyl ether, carboxyl and/or hydroxyl, or in thatsalicylic alcohol is used as complexing agent, the phenyl radicaloptionally being able to contain further substituents such as alkyl,halide, alkyl ester, alkyl ether, carboxyl and hydroxyl.
 13. Elastomermaterial according to claim 1, wherein, as complexing agent,α-hydroxycarboxylic acids are used.
 14. Elastomer material according toclaim 1, wherein, as complexing agents, compounds with protected OHgroups are used.
 15. Elastomer material according to claim 1, whereinseveral complexing agents are used.
 16. Elastomer material according toclaim 1, wherein combinations of boric acid complexes with varyingstructure and composition are used.
 17. Elastomer material according toclaim 16, wherein, as complexing agent, 4-tert.-butylpyrocatechol isused in combination with an aliphatic OH-functional compound. 18.Elastomer material according to claim 1, wherein the boric acidcomplexes are used together with other starters.
 19. Process for thepreparation of elastomer materials based on N-alkylaziridino compoundswith a base component which contains an aziridino compound and with acatalyst component which contains at least one acid-acting compound,both components being mixed before use, wherein, as the acid-actingcompound of the catalyst component, one or more boric acid complexes areused which can be obtained by reaction of boric acid and/or a boric acidderivative with at least one OH-functional compound, the OH functionsbeing able to be present wholly or partly protected, and this reactionbeing carried out either as an upstream reaction between boric acidand/or a boric acid derivative and at least one such OH-functionalcompound or during or after the preparation of the catalyst component orby mixing the catalyst component with the base component which thencontains at least one such OH-functional compound and the at least oneOH-functional compound containing at least one and up to 10 OH groupshas the general structural formula

wherein R1, R2 and R3 represent the same or different radicals selectedfrom she group consisting of hydrogen, aliphatic, cycloaliphatic,aromatic and araliphatic substituents with 1 to 30 C atoms in each, ofwhich one or more C atoms can be replaced by

R1′ an R2′ being the same or different wherein R1′ and R2′ arealiphatic, cycloaliphatic, aromatic or araliphatic bivalent radicalswith 1 to 30 C atoms.
 20. A dental molding comprising the elastomermaterials according to claim
 1. 21. Kit which contains the basecomponent and the catalyst component according to claim 1 separatelyfrom each other.
 22. The dental molding according to claim 20, whereinthe dental molding is a bite-registration material or a doublingmaterial.
 23. The elastomer material according to claim 9, wherein themolar ratio between boric acid and the OH-functional compounds is 1:1 to1:4.
 24. The elastomer material according to claim 9, wherein the molarratio between boric acid and the OH-functional compounds is 1:1.5 to1:3.
 25. The elastomer material according to claim 13, wherein theα-hydroxycarboxylic acids are selected from the group consisting ofglycolic acid, mandelic acid and benzilic acid.
 26. The elastomermaterial according to claim 14, wherein the compounds with protected OHgroups are silylated.
 27. The elastomer material according to claim 18,wherein the other starters are sulphonium starters.